Upgrading KEF 104/2 Cross Overs

I have a pair of KEF 104/2 speakers and have loved them since they were launched way back when they were about the same cost as my hole years salary ! I intend to keep them for life and want to research the best possible cross over upgrades and then upgrade them of course, now that I am of reasonable means and my speakers are around 24 years old (single wire not bi wire Raymond Cook versions)I am not putting a budget on this quest although common sense will prevail at the end.

I want to ask those in the community for the best advise, methods, components, circuit diagrams and electronic values in any upgrade with a view to my doing the work myself and or an electronics engineer to match and pre test the finished product.

Please could anyone who is in the know give me direction here as I want to plan and begin this soon, I listen to them through reasonably good source equipment and just in case amplification is a consideration I have a Nu-force P9 Preamp and P9V3SE Mono Block Power Amps we all live very happily together in Vancouver Canada, I would greatly appreciate anyone's comments and results in doing so them selves I have aa couple of ideas so far from other avenues but want to get some solid direction before my committing to the project !!!

Many thanks
Vancouver Audio Speaker Clinic
I've done surgery on about a dozen pairs of speakers by simply upgrading the crossover components and wiring.

First, do only one speaker at a time so that you can look at the untouched crossover for reference in case you get lost. I sketch a diagram of the crossover components I am replacing and the wiring to the drivers. I also photograph the crossover before touching anything.

Then I order my caps to match the values of the original. Upgraded caps are oft much larger physically, so you need to purchase them with long leads so you can physically fit them on the board. Replacement wiring needs to be the same diameter to fit through original holes in the crossover board, so don't go nuts purchasing large awg that won't work.

When all of the pieces are received, solder off the old parts of the crossover to be replaced and reassemble with upgraded. Test drive the speaker to make sure it works before doing the second. Good luck
Sorry to be a downer but I wouldn't spend any money to upgrade your 104.2s. I believe putting new crossovers and drivers in them changes these wonderful speakers. My pair of 104.2s are 29 years old, I purchased them new, they finally gave out and I couldn't find any original replacement parts. I can't complain since I did enjoy them for many years.